Method of operating compound compressed-air engines.



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Patented Mar, 29, 1910. l

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'0. B. HODGES.

METHOD OF OPERATING GOMPOUND GMPRESSED AIR ENGINES.

APPLICATION FILED JUNE 11, 1909. Patented Mar. 29, 1910.

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rasata CHARLES B. HODGES, F PITTSBURG, PENNSYLVANI, ASSIGNOR TO H. K. PORTER COMIANY, 0F PITTSB'UEG,

PENNSYLVANIA, A. CORPORATION OF PENNSYLVANIA.

METHOD OPERATING COMPOUND COMPRESSED-AIR ENGINES.

Application ledJune 11, 1909. Serial No. 501,641.

To all whom 'it may concern:

Be it known-that I, CHARLES B. Horses, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Operating Compound Compressed Air Engines; and I do hereby declare the following'to be a full, clear, and exact description thereof.

Bly invention relates to methods of operatii'ig compound compressed air engines, its object being to so operate the same as to obtain increased power from the compressed zur.

It consists, gene-rally stated, in operating such compressed air engines by carrying the compressed air through and expanding it in one cylinder and thereby reducing it below lpwcst atmospheric temperature, re-heating t 1e pressure by extended exposure thereof to air heating at atmospheric temperature and thereby increasing the volume thereof ,and carrying the re-heated air through a low pressure cylinder.

The invention also includes the utilization of the compressed air in such way as to obtain approximately the -proper balance as between the two cylinders of a compound compressed air engine so that the power generated in each will be approximately the saine according to 4the pressure of the air as utilized in the respective cylinders.

In the accompanying drawings Figure 1 is a side view of a locomotive engine adapted for the use of the invention, and Fig. 2 is a side view partly broken away on the opposite side thereof; and Fig. 3-is a cross section on the line 3-3 Fig. 2, and Fig. 4 is a longitudinal section partly broken away of the preferred form of the interheater and Fig. 5 is a cross section of said interheater.

To accomplish the above results in the apparatus best adapted for the purpose and as applied to, for exam le, a locomotive engine, I employ the main air reservoir 1 supported on a suitable locomotive truck or underframe 2 mounted on the driving wheels 3 Aand 4 onthe two sides ofthe locomotive. On the high pressure side, as shown in Fig. 1, the high pressure engine is shown at 5 connected up to the wheels 3, while on the other side the low pressure engine is shown at 6 connectedto the wheels 4e. The auxiliary reservoir 7 is supported on the main reser- Specijication of Letters Patent.'

exhaust air when confined and at lowv Patented Mar. 2e, ieio.

' Avoir 1 and air is fed thereto from the main reservoir through a suitable reducing valve 8, bringing the air to proper pressure for entrance to the valve box of the high pressure cylinder 5. The pipe 9 leads to the high pressure cylinder and has located therein the operating or throttle valve 10.

From the high pressure` cylinder 5 the air passes to the air inter-heater 11 -through the pipe 12 and from the same through the pipe 13 to the valve box of the low pressure cylinder 6, the air escaping therefrom through the pipe 14e which preferably exhausts into the nozzle 15 of the air interheater 11 to induce a draft through the same for the re-heating of the air discharged from the high pressure cylinder. The best results are obtained when the air enters the high pressure cylinder at a pressure of about 2 5() pounds and discharges therefrom at a pressure of about pounds, and is raised by reheating by atmospheric heating to about four' volumes of the original compressed air, so that the low pressure cylinder has a cubical contents of about four times that of the high pressure cylinder; for example, the

high ressure cylinder having a diameter, say, of) about 5 inches, and the low pressure cylinder having a diameter of about 10 inches.

Any suitable receptacle for reheating the compressed air by `the reheating action of atmospheric air between the high pressure cylinder and low pressure cylinder may be employed, and the travel of the atmospheric air over the surfaces of such receptacle can be induced in any suitable way. The preferred form of inter-heater is illustrated in Figs. 2 and 3, being supported in horizontal position on extending for practically the full leno'th thereof, being of small diameter and relatively great length to provide for a relatively strong or violent draft of air through the tubes thereof for re-heating of the compressed air. In the best form, as heretofore used when the engines are ten inches stroke and the cylinders tive and ten inches in diameter respectively, the inter-heater is about ries of baiiles '19 between the tubes 16 so as the side ofr the main reservoir,

to ca use the ycompressed air to be re-heated to travel in circuitous course around the reheating tubes. The atmospheric air is carried through the tubes 16 by the draft 1nduced Within the exhauster nozzle 15, such as by the discharge of the exhaust air from i 250 pounds.

the low pressure cylinder through the pipe 10. Air under pressure may also be einployed for inducing the draft such as by the pipes 19 leading from the pipe 13,v and controlled by the valve 20.

In the practice of the invention with the apparatus above described, the compressed air is stored at a relatively high pressure, say, about 800 pounds, within Ithe main reservoir 1 and it is maintained within the auxiliary reservoir 7 4at the desiredpressure forl the operation of the engine, say about Upon the operation of the throttle valve 10 it passes into the high pressure Vcylinder 5 and does work therein, escaping therefromat a relatively low pressure, for example, in the best practice at a pressure of about 50 pounds. The sudden and rapid expansion of the air within said high pressure cylinder causes a violent drop in the i temperature of the air, bringing it below lowest atmospheric temperature-z'. e., reducing it far below the temperature of the surrounding atmosphere. For example, if it enters at average atmospheric pressure of 60 Fahrenheit, the air passes therefrom at a temperature Abelow lowest atmospheric temperature, the reduction in temperature being usually about 14t0o F., so that it is brought to a temperature of about below zero F. At such low temperature the volume of air is insufficient to fill the low prcssure cylinder at a pressure of 5() pounds and if utilized at such low temperature the apparatus will be quickly lclogged through'the gathering of frost, freezing of the lubricant, and from other causes. I therefore discharge the exhaust from the high pressure cylinder into a suitable receptacle and utilize the atmospheric air for re-heating the compressed air when so confined by carrying the atmospheric air over the exposed surfaces of such receptacle, for example, through the tubes of the inter-heater 11, preferably using for this purpose the exhaust air from the low pressure cylinder. By such exhausta violent draft of atmospheric air is carried .through the tubes of the inter-heater, and as the compressed air travels around said tubes it is re-heated by the atmospheric air and raised thereby approximately to or approaching atmospheric temperature, and it is thereby increased in volume, a sufiicient volume for utilization Within the low pres sure cylinder of relatively greater cubic contents than the high pressure cylinder being obtained.

In practice I ind that by making the low pressure cylinder about four times the cu inch utilized in such cylinder is 200 pounds,

while in the low pressure cylinder at 50 pounds and four times the piston area the total pressure exerted is the same. Of course this may be varied asrfound desirable, but within practicable limits the expansion Within the high pressure cylinder is such as to reduce the temperature of the air at least 100O F., and the low pressure cylinder is made of such size as to utilize the conrpressed air according to 'the relative reduction in pressure, and the air is re-hcated within the inter-heater to bring it. to the proper volume according to the relative sizes vot' the high pressure and lou' pressure cylinders. By thus providing for the rapid expansion of the high pressure air and providing by yatmospheric re-heati'ng for the necessary increase of volume of the expanded air to provide for its utilization within the low pressure cylinder, practically all of the power t-o be generated from the compressed air is obtained and I am enabled lo utilize atmospheric heating through the carrying of the expanded compressed air through the inter-heaterin such way as to give proper exposure to the atmospheric air for the re-heating thereof, and such re-hcating is obtained without the expenditure of power other than that suiicient to expose the compressed air to proper atmospheric re-heating between the high pressure cylinder and the low pressure cylinder, and at the saine time to balance the power obtained so as to utilize the force generated upon the same driving shaft and balance that power in the operation of the engine, so utilizing practically all `the power tol be generated from the compressed air.

In order to insure a suiiicien draft through the inter-heater to re-heat the air entering the same from the high pressure cylinder and increase its volume to the full extent to obtain the desired power therefrom in the low pressure cylinder, instead of or in addition to the use of the exhaust.

air from the lou' pressure cylinder, I muy introduce a jet of air under pressure into the nozzle of the inter-heater; for example, by means of the pipe 13 taken from the pipe 13 as above described.

The general apparatus employed for the practice of the method-set forth herein granted to me Getober '15, 1907. d

The special ,method of inducing acurrent of air at atmospherictemperature overthe surface of the conining receptacle by a jet of air at as high pressure as that entering, the low pressure cylinder, for example as that passing through the pipe 13', forms the subject matter of a separate `application filed bv me of even date.,herewith, SerialfNo..

scirio.

The specic apparatus illustrated in this-4 application an involving the employment of ian air inteiheater having a lon contracted body of small" ldiameter fille with alarge number of. tubes of small diameter f und a p ipe carrying Fair' l"from the pipe lead- Vmg to the low pressure cylinder for inducing a draft over the exposed surface of the air interheater, forms the subject mat-ter of un application filed by `me ofeven date' herewitl'i, Serial No. 501,643

` That lclaim is:

l. The method of operating compressed nir engines, consisting incarrying"the air .at high 'pressure through and expanding it in;

one. lcylinder and thereby reducing it below,

lowest vatmospheric temperature, ree-heating the exhaust air from said. cylinder when con-f inedby extended exposure to air heating at atmospheric temperature and thereby in' cileusing the volume thereof and its capacity to generatepower, and carrying the re-'hea-ted air through a 10W pressure cylinder'.

2. The method ofI operating compressed pressure throughfone cylinder and there reducing it belowY atmospheric temperature, confining such air Within a receptacle v'and by 'a jet of air under pressure lnducing a ceases disclosed in' Letters Patentv Nm 868,560,

current of at atmospheric temperature over the exposed surface of such receptacle and thereby renee/ting and increasing the Volume of such exposed air, and carrying the reheated airthrough a 10W pressure cylinder. f

3. ".jlhe method of operating compressed air engines, consisting in carrying the air at high pressure through and expanding it one cylinder and thereby reducing it below lowest Aiatmospheric temperature, re-heating the exhanst air ii'rom' nsaid cylmder'when confined by extended exposure to airheating at atmospheric. temperature aidjhere; by increasing the volnmethereof, and carrying the :re-heated air through a,loW pressure cylinder, andso discharging the exhaust therefrom as to induce a draft over the exposed surfaces of the receptacle contining the exhaust air'rom the high pressure cylinder. 't r" e. Themethod of operating compressed air engines, consisting in carrying the. air

athigh pressureithrough and expanding it in one cylinder and thereby reducingl it be- `lowloWest atmospheric temperature and reerrantes n, Honors.

Witnesses Roemer C. loir'rrm 

